#include<bits/stdc++.h>
using namespace std;
long long factorialFn(int n)
{
//	int res = 1;
	if (n == 0) {
		return 1;
	}
	return factorialFn(n - 1) * n;
}
int main()
{
	int n;
	cin >> n;
	cout << factorialFn(n) << endl;
	return 0;
}
//07-11 12:06:22


